Subject: Re: [Isis-wg] Regarding document for best current practices

From: Jeff Learman <[email-masked]>
Date: Tue, 08 Jan 2002 11:49:21 -0500

Vishwas,

You repeated your request for a new document on IS-IS, either a
compendium of best practices or a new spec that describes Integrated
IS-IS.  One response I saw was that there weren't many discrepancies
between spec and practice, and that most "best practices" were matters
of implementation, not specification.

I suspect that there are things that would be good to document, and perhaps
padding of IIHs is one.  If you were to go over the list of potential issues
and present it, it might generate some interest.  I doubt that this is work
that anyone is eager to take on out of public interest, but if you are
willing to drive the work, I'm sure you would get lots of feedback ;-)

Concerning creating a new spec that combines ISO 10589 and RFC-1195,
this sure would be nice for those trying to learn integrated IS-IS
and newcomers to the field.  However, there are significant issues:

  1.  It would be a lot of hard work.

  2.  Any new wording of these specs would create new ambiguity problems.
      Which spec would be the definitive one?  Would the new document be
      definitive or just descriptive?

  3.  There would be a temptation to "fix" things, which would be a disaster.
      If there is any new text, it should start out with the intention of
      being identical in meaning to the previous specs.  Unfortunately,
      this would make it less helpful and clear for the IP-only crowd.
      But at least, it could be used as a starting point, so that any
      changes could be written against it, and therefore anyone could
      tell what changed between two subsequent versions.

All of these issues could be worked through, if there is enough commitment
among all players.  But I doubt that we will find this kind of commitment,
and I question whether the result would justify the amount of work and
haggling that would be required.

Alternatively, someone could write a good book on implementing IS-IS.
They'd probably sell upwards of 50 copies ;-)

Regards,
Jeff

Disclaimer: This is my opinion.  I do not represent Cisco in this
forum and I have never worked on IS-IS at Cisco.

At 10:34 AM 1/2/2002, Manral, Vishwas wrote:
>Dave,
>
>Changed the subject line to actually reflect the contents of the discussion.
>
>No matter how small the difference, don't you think it would be good to
>document it somewhere(may be, "not all that sticky" issues, could be
>documented too)?
>
>To think of it, wouldn't it be nice, if we could actually have an
>informational document(all ISIS work in IETF is informational anyway, I
>guess) which could talk about ISIS for IP specifically. This could talk
>about the entire protocol(instead of a delta with the ISO spec as in
>RFC1195) and could incorporate the best current practices. 
>
>Would there be any interest in the group for this kind of a document? I
>personally feel it would be a good idea, and would help in easier
>understanding and better implementation of ISIS(atleast for those who are
>not all that well versed). I have no idea of the IETF/ISO laison though.(I
>tried to check if this thing had been raised before in the mailing list
>couldn't find it)
>
>Thanks,
>Vishwas
>
>
>---------------------------------------------------------------------
>I think the number of things that are done in practical conflict with
>the spec is vanishingly small, where "practical conflict" is
>interpreted as "a reasonable implementation would notice."
>Excessively pedantic boxes have a way of fixing themselves one way or
>another.
>
>Most of these things are pretty obvious to anyone reasonably versed in
>the art, though the potentially sticky ones (like not bothering with
>ISHs) should probably be documented.
>
>--Dave
>_______________________________________________
>Isis-wg mailing list  -  [email-masked]
>http://external.juniper.net/mailman/listinfo/isis-wg

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---

From: Tony Przygienda <[email-masked]>
Date: Tue, 08 Jan 2002 09:53:15 -0800

Jeff Learman wrote:

> <snip>

We do not have really a framework for normative or definitive documents in this
group since
    a) we publish informationals
    b) it's not in the charter really
    c) ISO is the normative side for anything but IP features

> They'd probably sell upwards of 50 copies ;-)

there is at least one very good book (IMHO and if the author followed my
comments ;-) in the immediate pipe by a well-known serious publisher.
To stay unbiased, I'm not giving any further information ...

    thanks

    -- tony